As the excellent combination of mechanical properties and corrosion resistance for super duplex stainless steel, a prospective method-Wire and Arc Additive Manufacturing-for fabricating this material was proposed, and a wall component was deposited in this study. The microstructure of the as-deposited wall was carefully analyzed along with the variation of mechanical properties. The results revealed that, in the wall-body, the austenite/ferrite phase balance was broken by the overgrowing the austenite phase. During this process, the intergranular secondary austenite leading the increase of austenite phase together with some contributions made by the precipitation of intragranular secondary austenite. Propagation of the intermetallic phases, chi and sigma phase, was not the major reason for the low impact toughness in the last layer area and the root region. Instead, the presence of CrN and "inclusions" (Cr2N and impurities) took the main responsibility not only in the impact toughness but also the ductility. The anisotropic analysis revealed that the UTS and elongation appeared distinct difference in vertical and horizontal direction samples. The varieties in YS were eliminated by the nitrogen work hardening effect to a large extent.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

No abstract

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Maraging steel gains ultrahigh strength through aging; however, wire plus arc additively manufactured maraging steel features a columnar-dendritic structure with associated segregation and shows a much less pronounced aging response. In this paper, plastic deformation was introduced through interpass cold rolling during the layer-by-layer deposition process. After aging, the ultimate tensile strength (UTS) was improved substantially from 1410MPa (unrolled) to 1750MPa (50kN rolled). Rolling induced partial recrystallization to break the dendritic structure and form high-angle grain boundaries, which promoted the atoms diffusion to enable a more uniform solutionizing process and improved the subsequent aging response by 105-110%. The main contribution of overall strengthening of the rolled alloy was attributed to the effective aging process, accounting for more than 95% of the entire strength increase.